It's well worth the money as long as you remember it is partially fiction. His portrayal of Lincoln as politician is masterful. To quote from his "Note to the Reader"

"If you want to look over the author's shoulder, consult "Sources and Commentary" in the back of the book. That underbook separates fact from fiction and makes judgments on the historical controversies raised.

In general, the credibility quotient is this: if the scene deals with war or politics, it is fact; if it has to do with romance, it is fiction; if it is outrageously and obviously fictional, it is fact."